1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor probe having resistive tips of uniform height.
2. Description of the Related Art
As the demand for compact electronic devices such as portable communication terminals increases, there is a need for ultra compact and highly integrated nonvolatile recording media. A conventional hard disc can not be easily made into compact form, and high integration of flash memory is hard to achieve. Therefore, an information storing device using a scanning probe has been proposed.
A scanning probe is used in a variety of Scanning Probe Microscopy (SPM) techniques. For example, the scanning probe is used in a Scanning Tunneling Microscope (STM) that reproduces information by detecting current flowing between the scanning probe and a sample, an Atomic Force Microscope (AFM) that utilizes atomic force between the scanning probe and a sample, a Magnetic Force Microscope (MFM) that makes use of force between a magnetic field and the magnetized scanning probe, a Scanning Near-Field Optical Microscope (SNOM) that overcomes a resolution limit due to the wavelength of visible light, and an Electrostatic Force Microscope (EFM) using electrostatic force between a probe and a sample.
In order to record and reproduce information with high speed and high density using the SPM technique, surface charges on a small region having a diameter on the order of tens of nanometers must be detected, and cantilevers must be manufactured in an array for improving recording and reproducing speed.
International patent publication No. WO 03/096409 discloses a method of manufacturing a semiconductor probe having a resistive tip. The method includes forming a mask in a stripe shape on a substrate, and forming a resistive region under the mask through ion implantation and an annealing process. Next, a mask in a rectangular shape is formed by etching the mask using a photomask having a strip shape, which is perpendicular to the mask, and tips in which the resistive region is self-aligned is formed by etching the substrate using the rectangularly shaped mask.
FIG. 1 is a drawing which illustrates a conventional method of forming a resistive tip using a mask having a rectangular shape;
Referring to FIG. 1, when etching an upper surface of the substrate 10 using a rectangularly shaped mask 16 having a width of approximately 2 μm, a peak forming portion composed of electrode regions 11 and 12 and a resistive region 14 is formed. At this time, the width W of a tip neck formed under the mask 16 varies according to the degree of etching. The width W of the tip neck is an important parameter for determining the height of the tip. The height of the tip can vary according to the width W of the tip neck when performing a thermal oxidation process for forming a sharp peak after removing the rectangular mask 16. In a scanning probe device using a plurality of cantilevers in an array, the height of the tips must be uniform. If the height of the tips is not uniform, there is a problem in simultaneously reading and writing with the cantilevers. In order to adjust the height of the tip to approximately 1 μm, the width W of the tip neck can be managed to approximately 300 nm. The width W of the tip neck during an etching process is measured by a faint shadow through the mask 16 using an optical microscope.
However, measurement of the width W of the tip neck using an optical microscope is not correct since the width W of the tip neck is estimated by a faint shadow. Therefore, there is a drawback in that the height of the tip is not manufactured within the desired range.